Die for drawing sheet material



p 1956 M. s. SCHNELL 2,761,406

DIE FOR DRAWING SHEET MATERIAL Filed May 25, 1954 7 Sheets-Sheet l mu.1H l 117 1 "'5? 19 17 31 HI K /21. [w I 23 f I INVENTOR- MICHHEL S.,S'cunsu.

HTTORNEV Sept. 4, 1956 M. s. SCHNELL 2,

DIE FOR DRAWING SHEET MATERIAL Filed May 25, 1954 7 sheets-sheet 2 INVEN TOR. MICHHEL S. SCHNELL HTTORNEV Sept. 4, 1956 M. s. SCHNELL2,761,406

DIE FOR DRAWING SHEET MATERIAL Filed May 25, 1954 7 SheetsSheet 3 I'Hiliii d i 15 wfll l' l 22 I if 30. I1 E 1 I 23 Hi INVENTOR. MICHHEL S.SCHNELL HTTORNEV Sept 1955 M. s. SCHNELL 2,761,406

DIE FOR DRAWING SHEET MATERIAL Filed May 25, 1954 7 Sheets-Sheet 4 IINVENTOR. MICHFIEL 5'. S'CHNELL HTTORNEV P 4, 1956 M. s. SCHNELL2,761,406

DIE FOR DRAWING SHEET MATERIAL Filed May 25, 1954 7 Sheets-Sheet 5 IN VEN TOR. MICHHEL S, ScHMELL Flnormzv p 1955 M. s. SCHNELL 2,761,406

DIE FOR DRAWING SHEET MATERIAL Filed May 25, 1954 7 Sheets-Sheet 6 28-"Q/IZ F 6 W H W Hiiii '!z g min w '1.

I 32 22 2O 1. 30 I IN VEN TOR. Mam-mm. S. SCHNELL HTTORNEV United StatesPatent DIE FQR DRAWING SHEET MATERIAL Michael S. Schneil, Salem, OhioApplication May 25, 1954, Serial No. 432,207

2 Claims. (Cl. 113-46) The present invention relates to dies for drawingsheet material, more particularly to multiple stage dies wherein thesheet material is subjected to a plurality of drawing operations withina single die, and the principal object of my invention is to provide newand improved dies of the character described.

In the sheet metal drawing art it is well-known that the amount of drawto which sheet metal may safely be subjected in a single operation isquite limited. The limitations, of course, depend upon thecharacteristics of the particular metal being drawn, the thickness ofthe metal, the shape of the drawn article and many other factors.Because of these limitations, it has been customary to perform a seriesof drawing operations in order to achieve the desired final form.

In the past, a series of drawing operations necessitated a series ofdies through which the sheet metal was successively passed. Accordingly,each die required a separate press, an operator for each press, and theadded operation and expense of transferring the pieces from one die tothe next. Furthermore, because of work hardening, it was usuallynecessary to anneal the pieces between the various drawing operations.

In Letters Patent No. 2,602,411, issued to me July 8, 1952, I disclose adie which performs two drawing operations at a single stroke of thepress. The use of this die eliminates certain disadvantages of prior artdrawing dies; however, since this die performs but two drawingoperations, other dies may still be required if the piece to be maderequires more than two draws.

The present invention discloses a die which performs more than twosuccessive drawing operations in producing a deep cup from a flat, sheetmetal blank. Since these operations are performed on a single press,great savings are achieved because only one operator is required, only asingle press and die are employed, and because annealing between drawsis eliminated. These and other advantages will become apparent from astudy of the following description and from the drawings appendedhereto.

In the drawings accompanying this specification and forming a part ofthis application there are shown for purposes of illustration, twoembodiments which my invention may assume, and in these drawings:

Figure 1 is a fragmentary sectional view of a four stage die showing theposition of parts just prior to the first draw operation,

Figure 2 illustrates the position of parts at the completion of thefirst draw,

Figure 3 illustrates the position of parts at the completion of thesecond draw,

Figure 4 illustrates the position of parts at the completion of thethird draw,

Figure 5 illustrates the position of parts at the completion of thefourth or final draw,

Figure 6 illustrates the position of parts during ejection and removalof the drawn piece from the die, and

Figure 7 is a fragmentary sectional view of a three Patented Sept.4,1956

stage die showing the position of parts just prior to thefirst drawoperation.

Referring to Figures 1 through 6 and with particular reference to Figure1, it will be seen that my novel die comprises a die body 10 having adie cavity 11 adapted to be secured to the bolster of the press (notshown). A sleeve-like punch 12 is adapted to be secured to the ram ofthe press (not shown) and a drawing ring 13 is adapted to be secured toa blank holder plate 14.

As will be understood, plate 14 may be actuated by an auxiliary slide ifthe press employed is of the double-acting type. However, if asingle-acting press is employed, the plate 14 may be actuated by the ramof the press, any suitable well-known mechanism being interposed betweenthe plate and the ram to provide for the necessary overtravel of theram. A blank holder 15 is also adapted to be carried by the plate 14,springs 16 being interposed between the blank holder 15 and the plate 14for a purpose to be disclosed.

The die body 10 has an external drawing surface 17 adjacent the mouth ofthe die and this drawing surface is proportioned for cooperation with aninternal drawing surface 18 of the drawing ring 13. It should be pointedout that where cooperating drawing surfaces are herein mentioned, it isto be understood that such surfaces will be spaced apart a distanceconsistent with the thickness of the metal being drawn. The die body 10also has a drawing surface 19 adjacent its mouth which is cooperablewith the exterior of the sleeve 12 to draw the sheet metal therebetweenand in the embodiment disclosed, the drawing surfaces 17 and 19 areformed at external and internal surfaces of a ring 117 which is suitablysecured to form the upper part of the die body 10.

A die post 20 having a rounded-end portion which corresponds to thedesired shape of the end-wall of the piece to be drawn is positionedwithin the cavity 11 of the die body 10 and comprises an outer portion21 in fixed relation with the die body and an inner portion or ram 22which is slidable Within the portion 21. As will later be described, theinner ram portion 22 of the die post 20 is shiftable upwardly (in theposition of parts illustrated) preferably by means of a fluid cylinder23 which is secured to the bolster of the press.

In the relation of parts herein illustrated, the lower end of the sleeve12 is provided with an external drawing surface 24 which is cooperablewith the aforementioned drawing surface 19 of the die body and the lowerend of the sleeve is also provided with an internal drawing surface 25which is proportioned for cooperation with the exterior of the outerportion 21 of the die post 20. The interior of the sleeve 12 is alsoprovided with an internal drawing surface 26 which is spaced from theend of the sleeve and which is cooperable with the exterior of theportion 22 of the die post 20.

A member 27, which has a lower face contoured to fit with the end-wallof the piece to be formed, is normally positioned within the sleeve 12adjacent the drawing surface 24. Member 27 is secured to a piston rod 28of a fluid cylinder 29 (see Figures 4 and 5) which is fixedly carried bythe sleeve 12 and the member 27 functions more or less as an articleholder during the final draw operation and also functions as a knock-outto eject the finished piece from the die.

The cavity 11 of the die body 10 is enlarged at 3% to slideably receivea pressure ring 31 which is contoured to fit with the lower end of thesleeve 12. The ring 31 is slideable on guide pins 32, and resilientmeans, such as springs or the like (not shown), yieldably urge the ring31 to its upper position shown in Figure 1, such position being definedby abutment of the ring 31 with a shoulder formed in the cavity 11.

Operation of the die herein disclosed is as follows:

With the die parts separated as shown in Figure l, a blank B may bepositioned on the die body 10, and the press (not shown) operated tolower the sleeve 12, the blank holder plate 14, and the associated partscarried thereby Suitable well-known means, not herein. shown, may beused to properly gauge the position of the blank 8 relative to thedrawing surfaces of the die body 10. As the aforementioned parts movedownwardly,.the blank holder 15 will engage the stock to firmly hold itin position. Continued movement of the press will compress the springs16 and cause the drawing ring 13 to move into engagement with the blankand thus draw the outer portion thereof between the drawing surfaces 17,18.

At the completion of the'first draw and with the parts in the positionshown in Figure 2, movement of the blank holder plate 14and itsassociated parts will be arrested while downward movement of the sleeve12 will continue. (It will be understood that this movement will beprovided for by any suitable, well-known press construction which neednot be described in detail.) The cup shaped piece formed duringthe firstdraw will thereupon be drawn between the drawing surfaces 19, 24 toinvert the cup and form it to a smaller size positioned about theexterior of the lower portion of the sleeve 12 (see Figure 3)} It willbe noted that at the completion of the'second draw and as shown inFigure 3, the sleeve 12 has carried the piece into engagement with thepressure ring 31.

Continued downward movement of the sleeve 12 from the position shown inFigure 3 will position the sleeve about the die post 24 and will thusonce again invert the piece since it will be drawn between the drawingsurface 25 and the exterior surface of the outer portion 21 of the diepost to the position shown in Figure 4. During the operation ofinverting the piece over the outer portion of the die post, the pressureexerted by the ring 31 will prevent wrinkles from forming in the piece.

At the completion of the third draw and as shown in Figure 4, the endwall of the-piece will be positioned between the die post 29 and'themember 27. Movement of the portion 22 of the die post in an upwarddirection against the now stationary sleeve12 by means of the fluidcylinder 23 will draw the piece between the drawing surface 26 and theexterior of the inner portion 22 of the die post. During this operationthe cylinder 29 will exert sufficient pressure aginst the end-wall ofthe piece to prevent stretching and thinning of such wall.

Upon completion of the final draw and with the parts in the positionshown in Figure 5, the fluid pressure in the cylinder 29 will bereleased, cylinder 23 will'be actuated to return portion 22 to itslowermost position as shown in Figures 1, 2, 3, 4 and 6, and sleeve 12together with blank holder plate 14 will be raised to the position shownin Figure 6. It will-be noted that as portion 22 is retracted, the piecewill be stripped from this portion by engagement with portion 21 and thepiece will be carried up with the sleeve 12 since the piece will tightlyengage the drawing surface 26.

Cylinder 29 will now be actuated to urge member 27 downwardly to theposition shown in Figures 1, 2, 3, 4 and 6 and this will eject thepiece'from the sleeve whereby it will fall into the cavity of the diebody It) as illustrated in full lines in Figure 6. The completed piecemay now be removed, another blank placed in position upon the die body,and the foregoing operations repeated to draw another piece from thefiat blank.

Figure 7 illustrates a three stage die which is similar to the diedisclosed in Figures 1 through 6 and in which corresponding parts havebeen indicated by similar reference numerals followed by the letter a.The die is shown in the open position immediately prior to the start ofthe drawing operation and it will be noted that in-this die the firstforming operation hereinbefore described has been eliminated. Sincethere is no necessity for the drawing ring 13, this part hasbeeneliminated and the blank holder 15a is secured directly to the 14aas' shown.

It is believed that since the die shown in Figure 7 is similar to theone hereinbefore described in detail, operation of this die will readilybe apparent.

In view of the foregoing it will be apparent to those skilled in the artthat l have accomplished at least the principal object of my inventionand it wiil also be appar cut to those skilled in the art that theembodiments herein described may be variously changed and modified,without departing from the spirit of the invention, and that theinvention is capable of uses and has advantages not herein specificallydescribed, hence it will be appreciated that the herein disclosedembodiments are illustrative only, and that my invention is not limitedthereto.

1 claim:

l. A drawing die for eifecting multiple stage draw reductions on sheetmaterial by a single die stroke, comprising a fixed die member havinga'vertical die cavity and provided with an internal drawing surface, ahollow upright die post fixed within said cavity and having an exteriordrawing surface disposed co-axially therewith, a

blank holder plate movable sleeve disposed co-axially with said diecavity,

said sleeve having an external drawing surface at its lower endcooperable with the internal drawing surface of said fixed die member,said sleeve also having vertically spaced interior drawing surfaces,said sleeve being movable into said die cavity for cooperation of itsexterior drawing surface with the internal drawing surface of said fixeddie member to engage and deform sheet material positioned therebetweeninto a cup-shaped shell having a closed end surrounding the lower end ofthe sleeve, further movement of said sleeve into said die cavitytelescoping the sleeve over said post so that the closed shell end ispushed into the moving sleeve by the upper post end, the lower interiordie surface on said sleeve cooperating with the exterior die surface onsaid post to turn said shell inside out into a similar shell of reducedWidth and increased length surrounding said upper post end, a rammounted for vertical movement within said hollow post, and means formoving said ram outwardly from said post to press against the closedinner end surface of the reduced shell to further reduce the width andincrease the length of the latter by pushing it through the upper ofsaid interior drawing surfaces of said sleeve.

2. A drawing die for effecting multiple stage draw reductionsonsheet-metal by a single die stroke, comprising a fixed die memberhaving a vertical die cavity and provided with internal and externaldrawing surfaces, a hollow upright die post fixed within said cavity andhaving an exterior drawing surface disposed co-axially therewith,amovable sleeve disposed co-axially with said die cavity and a movabledraw ring disposed co-axially with and surrounding said sleeve, saiddraw ring having an internal drawing surface cooperating with theexternal drawing surface of said fixed die member upon movement of ,saiddraw ring over and about the upper end of said die memberito engage anddeform a blank of sheet material positioned therebetween into acup-shaped shell surrounding said upper end of said die member, saidsleeve having an external drawing surface at its lower end cooperablewith the internal drawing surface of said fixed die member, said sleevealso having vertically spaced interior drawing surfaces, said sleevebeing movable into said die cavity for cooperation of its exteriordrawing surface with the internal drawing surface of said fixed diemember to engage the closed end of said shell and turn said shell insideout into a cup-shaped shell of reduced width and increased lengthsurrounding the lower end of said sleeve, further movement of saidsleeve into said die cavity telescoping the sleeve over said post sothatthe closed end of the reduced shell is pushed into the moving;sleeve by the upper post end, the lower in-- teriordie'surface on saidsleeve cooperating with-the 5 6 exterior die surface on said post toturn said latter shell References Cited in the file of this patentinscilde out ino1 a gstihmilar shglgjgf fgrlthegpredggzzl wiidtlr UNITEDSTATES PATENTS an increase en surrou g s 1 u er en ram mounted forvertical movement within said hollow 5 222 Hothersall June 1936 post,and means for moving said ram outwardly from 5 1 6 41 Butters 1886 saidpost to press against the closed inner end surface 2289199 g 1927 of thelast mentioned shell to still further reduce its 41 1 :3 July 1942 Widthand increase its length by pushing it through the Sc e July 1952 upperof said interior drawing surfaces of said sleeve.

